1) Field of the Invention
The present invention relates to a novel dihydropyridine derivative or a salt thereof and a pharmaceutical agent containing the same as an effective component thereof.
2) Description of the Background Art
So far a great number of compounds with strong calcium antagonism have been discovered in dihydropyridine derivatives. Among them, nifedipine, nicardipine, nimodipine and the like have been widely used as therapeutic agents for cardiovascular diseases, such as vasodilators and antihypertensives.
However, these conventional dihydropyridine derivatives have a number of problems including a high incidence of adverse effects and insufficient duration of the action thereof, so the derivatives have not been satisfactory.
Hence, expectation has been oriented toward a novel dihydropyridine derivative with excellent pharmaceutical actions and a high degree of safety, and a therapeutic agent for cardiovascular diseases containing the same as an effective component.
In such circumstances, the present inventors have carried out investigations intensively, and have found that the derivatives represented by formula (I) into which a dihydrobenzopyranyl group is introduced as the ester side chain of the dihydropyridine skeleton thereof have extremely strong, slow and prolonged vasodilating action, antihypertensive action and the like, and that the derivatives are useful as a pharmaceutical agent. The present invention was achieved based on the above findings.